Geeks who hit the site were sent to grepblogs-dot-net, a site that offers links to live adult webcams, erotic blogs and adult erotic fiction, among other things. Closing the Internet Explorer browser window that contains the site caused another link farm of dubious links to open, from a site called cnomy-dot-com. It carries more porno links and banner ads claiming visitors have won a free iPod.

"I was aghast," said Tom Christiansen, author of many of the most popular Perl reference books. "I need to understand the nature of the problem."

Christiansen is the owner of Perl.com, but has turned over day-to-day operations of the site to O'Reilly, a publisher of dozens of tech books and websites.

The redirection is the result of a change in ownership of the grepblogs-dot-net domain name. Judging from this link, the address was hosted on an open source ad server by the name of phpAdsNet. Effective Thursday, however, the site came under new ownership, according to Whois records.

The episode is the latest example of the perils that come from running ads and javascript from a third-party website. In recent months, rogue ads hosted on DoubleClick, Real Media and others have infected websites. While such services often make life easier for administrators, they also create opportunities for miscreants to defraud users.

Since 2006, HTML code on the Perl.com website has pulled javascript off of the grepblogs site, said Dale Dougherty, general manager of the O'Reilly divisions that's responsible for upkeep of Perl.com. Once the content on the grepblogs site changed, visitors to the site were soon redirected to other sites. O'Reilly admins fixed the problem at about 6:30 a.m. California time on Friday by nullifying the script.

Perl is a popular program among sysadmins, web developers and network programmers. It borrows liberally from languages including C, shell scripting and AWK.

It remains unclear if other websites inside O'Reilly or elsewhere are linking to the grepblogs site. Web searches came up empty, but because they didn't expose the Perl.com script, it stands to reason they wouldn't show scripts on other sites either.

If you find additional sites, please leave a comment below, or contact your reporter using this link. ®